Thanks for troubleshooting further.
Can you try with pre-loaded library workaround that was pushed to git master yesterday? Respectively:
* https://github.com/kamailio/kamailio/tree/master/src/modules/tls/utils/opens...
It looks like a side effect of not having the pthread locks initialized by libssl 1.1 with process shared option. If proves to work fine, then we can approach openssl project to introduce a way to allow setting the process shared option for locks.